The Hero and The Vampire
by To Whomever it May Concern
Summary: It was a sunny day in Ooo, as per usual and no one, especially Finn, expected anything different from a normal day of adventuring. But he was wrong, so very, very wrong... Lemons, Yaoi, Marshall is topping, Rated M for swearing and Slash See other warnings inside.


**Warnings: **Marshall Lee/ Finn, M/M, Yaoi, Lemon, Slash, Interdimensional Traveling, Some OOCness which I tried really hard to avoid but it is probably there

**Disclaimer: **I do not own Adventure Time or it's characters. I only own this fic and all the fanart I make of them. I am making no profit on this and blah blah blah.

**Summary: **It was a sunny day in Ooo, as per usual and no one, especially Finn, expected anything different from a normal day of adventuring. But he was wrong, so very, very wrong...

**AN: **This is my first completed oneshot and first completed fanfction. I hope you all enjoy reading it as much as I did writing it. Love this pairing! Took me many hours and many cans of Dr. Pepper, but now it is here. I present...*drum roll*... The Hero and the Vampire!

* * *

"C'mon, Jake!" Finn shouted, running out the tree house door waving around his sword.

"I'm coming, I'm coming. Just let me finish my game!" Jake shouted back.

"No way! PB said we had to go find the portal and destroy it before any other creepy shabizzles find their way out.

"Fine. B-mo?"

"Progress saved." B-mo said robotically before chuckling.

Jake leaped off the couch stretched himself so he simply landed outside.

"Bubblegum said it was at the top of Mount...Mount... sounds like damn, I forgot what it was called. Anyways it's that dark, ridgy, spooky looking one over there."

"Oh, you mean Mount Doom?"

"Yeah, that one. Let's go!"

Finn took off running but Jake used his powers to his advantage and lifted him onto his back and increased his size so that they covered almost five times as much ground as they would have without.

"Help! Help us!" Finn heard little cries.

"Jake, stop. Somebody needs help."

"But the port-"

"This is more important."

"Yeah, I know. Do your biz," Jake said dejectedly.

Finn dropped off his back as Jake shrunk down.

"What the flip? Housies again?"

"They are so pathetic." It was mean but it was true and that was the only reason Jake actually said it out loud, otherwise Finn would go psycho on him and tell the Boom Boom Mountain story again.

"Yeah, they really are. But that doesn't mean we shouldn't save them!" Leave it to Finn to always come back to his heroic tendencies.

They looked around. A few whywolves were after the little buggers because Donny wasn't here at the time apparently. He banker one had his framework bitten off and was hiding behind the well along with the new hospital Housie and other injured members of the village.

"Stop tormenting these housies again, whywolf!" Finn pulled his sword out of his backpack again and pointed it at the wolf threateningly.

"But Donny is _asleep_." He said "asleep" with an air of mischief in it and shared a glance with the rest of his pack.

"I saw that! Why'd y'all go and kill Donny? Sure, he was annoying, but that's no reason to kill a guy."

"We didn't _kill_ him. He really is just sleeping. But if you're going to make assumptions like that, I guess we _will_ have to kill _you_ to prevent more of those."

The speaker bared his teeth and snarled as he launched himself at Finn. They were moments away from collision when Jake jumped in the wolf's path, protecting Finn. Its teeth and claws dug into Jake's back and he cried out. He wasn't used to getting hurt because he always managed to dodge, but right now he was protecting Finn so the pain didn't matter. The wolf snarled and kicked and bit at Jake reducing him to his normal size. When Finn finally processed the blood spilling out of his best friend he lunged at the wolf stabbing the sword directly through its skull. The other whywolves ran off and the housies treated their wounds, bit Finn sat with Jake in his lap.

"Jake, bro, are you gonna be okay?"

"Mayb- Yes. Yeah, I just..." Jake coughed up some blood, "I just need to... rest."

"No! You can't die!"

"I won't die. Trust me. Look," he pointed at a smaller cut that was already scabbing over. "It will work faster if I sleep."

"Okay, then get in my backpack." Finn was already holding his backpack open for Jake.

"No, no, no, I can't weigh you down."

"But-"

"No buts. I'm going to rest here for a bit- with the housies- and then go back to the tree house, you destroy the portal."

"If I'm not back by..." Finn trailed off, noticing Jake was already asleep. "Sleep well, bro," he whispered.

Finn turned back onto the path through the forest to the top of the mountain where the portal was. He kicked stones and grumbled dejectedly. He tuned out all noises, even himself, and walked in complete silence. With all his attention turned to the ground, he arrived at the peak quickly and could see the portal.

"Yoo-hoo, Fi-inn!"

The sudden noise awoke him from his trance-like state and he instantly recognized the Ice King's high, nasal voice, but it was slightly different. No matter. Finn reached for his sword and grasped nothing, panicking, he tried his pockets and was about to check his backpack again when he remember it was still embedded in that why-jerk's face.

"No sword?" the Ice King taunted. "Too bad!" he launched a large snowball a Finn's chest aiming perfectly. The blow knocked Finn back, closer to the portal. The king kept at it and when Finn was only a few feet from the portal, the Ice King shot an icy gust of wind, blowing Finn directly in to the centre of the gateway.

On the other side, Finn caught a glimpse of the Ice King laughing before the portal closed completely. Now doing the only thing he could do, he decided to turn around. His adrenaline rushed as he began to turn and... everything was exactly the same. How disappointing. Wait! He could see Bubblegum only a little ways away. He ran towards her.

"Bubblegum!" he reached a hand towards her and when she turned around, it was a guy.

"Fiona," he laughed. "Why do you look like a boy?"

"Who's Fiona? I'm Finn."

"Ha, ha, very funny," the man said sarcastically.

"Wait, are- are you... Prince Gumdrop?"

"Prince Gum_ball_."

"Oh yeah, that's right."

The memories of that shitty fanfiction the Ice King wrote came flooding back to him. Was that all real?

"If you aren't Fiona, then who are you?" Prince Gumball asked.

"I'm Finn the Human, I came through a portal from over there," Finn pointed in the direction he came from. "I guess this is like an alternate dimension, or something."

"Oh my, how exciting..."

Prince Gumball started talking about science-y stuff and Finn automatically tuned it out.

"...So would you like to go back?"

"Huh?" Finn noticed Gumball was talking to him. "I don't think I need to, if it would be a hassle for you."

The male version of Bubblegum was more attractive than Finn had initially thought. The moment he hit puberty, he realized he didn't have a crush on her or Marceline, and that he liked men instead.

"Would you like me to introduce you to the town then?" Gumball asked, smiling.

"Sounds like a date."

"Excuse me?"

"Oh! Uh, sounds...great!" _Oh glob! How did I let that slip?_ Finn thought.

"Okaaay... Well, it appears that your alternate is Fiona, so we'll go to her first."

Finn told Gumball about his reality versus the one he was in now.

"So it seems that only gender is changed while personality and such remains the same."

"Yeah, I guess."

"Then you and Fiona should have a lot in common. And if you want, could you maybe ask her to finish the tour? I have a convention to attend. I'm sorry I didn't bring that up earlier. Here we are anyways."

They approached a tree house identical to Finn and Jake's.

"Sure, I'll ask."

"Great! I'll walk you to the door in case Fiona decides not to trust you."

"I don't need- Oh." He remembered his tendencies and figured out why it would be good for Gumball to stay with him.

Gumball knocked on the door.

A female voice shouted, "Who is it?!"

"Gumball."

There was some rustling and a pretty girl similar to Finn opened the door.

"Hey, Gumball and... uh, friend of Gumball."

"Oh, right! This is Finn the Human. He's from the portal at the top of the hill. Everybody who's male here is female there and vice versa. And he is your alternate. I apologize if this is rushed, but I have a conference to attend. Please let him stay with you."

"Oh, o-"

"Thanks. Bye, Fiona!" Gumball said running off.

There was an awkward silence for a few moments.

"So..." Finn said.

"Yeah..."

"Can I come in?"

"Oh! Yeah, of course."

"Fiona!" an unfamiliar voice said. "What was that about Gumb- Who's that?"

"This is Finn. Finn Cake, Cake Finn."

"Hi," Finn said somewhat sheepishly.

"Yeah, but who _is_ he?" Cake asked ignoring Finn.

"He's the alternate dimension version of me."

Cake pondered this new information, trying to make sense of it.

"So, uh, Gumball asked me to ask you if you would finish showing me around."

"Yeah, sure. You got a vampire where you're from?"

"Marceline the Vampire Queen. Duh," Finn said, forgetting they weren't from Ooo.

"I don't know any Marcelines, but I do know Marshall Lee the Vampire King. We'll go to him because after that there's only Cake's boyfriend, Lord Monochromicorn as somebody important."

"I guess he's like Lady Rainicorn."

"Sure. Let's go!"

Finn remembered saying that to Jake and felt tears well in his eyes. No! he was not going to cry.

"You okay?"

"Just remembering my best friend. I hope he's doing okay."

Fiona got what was going on and didn't ask more about it. They chatted at the walked to Marshall Lee's house in the cave. Fiona knocked on the door.

"It's Fiona!" she shouted in.

"Be there in a minute."

A male voice called back. But it wasn't just that to Finn, it was the voice of a thousand tenor angels combined into one voice box that managed to fit right into the throat of the male version of the vampire he used to lust for. Perfect.

Just as promised, a minute later Marshall opened the door clad in nothing but a maroon towel wrapped around his waist with his hair sopping wet and dripping. Fiona and Finn blushed equally violently; the only difference was that Fiona didn't now have a boner.

"Shit, if I had known you brought a guy I would have at least put some pants on."

That wouldn't have helped Finn because right now he was staring at the vampire king's perfect chest. Then he noticed that the other's nipples were starting to perk up from the combination of water and the coolness of the air outside. Not only did he have a boner at this point, but it was positively painful.

"Ha, ha. Anyways, this is Finn. He's me from an alternate dimension."

"Yo, Finny."

Cute nicknames did not help this issue he had going on in his pants, and for glob's sake, he just met the man!

Finn tried to speak but all that came out was a little half choked gasping noise. Marshall looked down briefly and a small smile crept onto his face. He floated back into his house.

"Come on in, we can get to know each other."

There was a hint of something suggestive in his voice that Fiona evidently didn't pick up on.

Not able to handle his "little problem" any more, Finn blurted out, "Can I use your bathroom?"

"Sure. Upstairs, third door on the right." It was a guy thing, Fiona would never understand. Unless... No, gross.

Finn calmly walked up the stairs and as soon as he was out of sight ran to the bathroom, locked the door and pulled down his shorts.

He had no idea he could get that big. "Damn!"

He washed his hands and then spit on his right. He grabbed hold of himself and started pumping.

"Oh, mother of glob, this feels so fucking good."

His mind wandered to Marshall. His perfect chest, the water dripping down his face, he imagine the towel falling off. His hand moved faster almost as if it had a mind of its own. Gog, why was Marshall so _sexy_? He felt the warmth coiling in his chest, not unfamiliar but not really familiar either. He just liked it. His thought of Marshall grew dirtier and dirtier the closer his climax approached.

"MARSHALL!" he shouted. And there was less than a second after that word was uttered where Finn realized _Oh shit_ and then he came. All over the place.

"Marshall!" they heard Finn shout from upstairs.

Fiona's instincts kicked in instantly but then Marshall said "You probably won't want to go in there." After a few moments she understood what he meant and her face turned so dark red she had to leave and walked back to the tree house.

Marshall floated up the stairs and knocked on the door, "We heard your little outburst."

"Shit." Marshall could easily make out the muffled response.

And he had to admit, Finn was actually really attractive and looked a lot older than his mere sixteen years. And it would be okay too, since Marshall was technically only eighteen.

"Fiona left, just sos ya know. And I completely understand."

Finn was staying as quiet as possible just in case Marshall might think he wasn't there.

"Can I come in?"

Finn thought for a bit. At least he had gotten the come off the floor and mostly off his clothes, and had his pants back up. And it wouldn't be right for him to keep a guy he just met out of his own bathroom when he came over uninvited. Finn knew enough about manners to know that wasn't something you should do.

"Okay."

"You'll need to unlock it."

"Right." Finn looked embarrassed as he unlocked and opened the door. "Hi," he said.

"Hi," Marshall replied as though they had just met.

They stood there for a bit and then Marshall spoke.

"There's only one reason that what just happened happened, and I know that reason, I also know what's going to eventually happen and that there's a long process to get to what's going to happen and because I know what you want and also what I want are at the end of that long process, so let's skip the awkwardness and just cut to the chase."

And with that he hooked his arm around Finn's mid back, pulling him to his bare chest and kissed him. Their eyes met before Finn closed his blissfully and in that moment, Marshall realized that Finn was different. That he wasn't someone he could just have a one night stand with because _one_, Finn was young and still believed in love instead of sex and would just keep coming back if Marshall tried to get rid of him, and _two_, Finn was special, something about him just struck something inside Marshall's unbeating heart, a hunger of some sort, a hunger that grew the more prolonged their kiss was.

Finn was running out of breath and pulled his head back, surprisingly, Marshall let him. Finn was panting.

"That was... amazing..."

He smiled, showing off his fangs. What was it about fangs than turned Finn on so? He grabbed Marshall's face and smashed his lips to the older teen's with far less romance than the first one. And soon, they got into it again and were practically eating each other's faces.

Marshall picked up Finn and he hooked his legs around the vampire's back making the towel slip, but no one cared. Finn was being smashed against a wall and all he knew was that he was upstairs in Marshall Lee the Vampire King's house being ravaged by the man in question and that it felt so, so good- no, fantastic. Marshall kissed up and down the young teen's neck lifting the edge of the hat so he could gain access, but not removing it. He remembered how Fiona spazzed when her hat was taken off.

"Go ahead, you can take it off," Finn said breathily almost reading Marshall's mind.

Marshall simply nodded and as he carefully lifted off the hat he brushed past a spot under Finn's ear and behind his jaw making him moan loudly. He tugged the hat off, releasing Finn's shaggy golden hair.

"Woah," was all Marshall managed upon seeing it.

He took Finn's mouth back into his own before kissing along the blonde's jawline until he reached the sensitive spot making Finn squirm and moan. Marshall began thrusting against Finn though the towel and his shorts. This was all getting to be too much for the younger teen. He was going to come again really soon. Marshall hoisted the younger teen up and carried him to his bedroom. He unceremoniously dropped Finn on the bed and began thrusting his erection against the other's again. Marshall nipped and licked at Finn's neck, the fingers of his left hand twisting through the golden locks.

"Marshall," Finn moaned quietly.

Marshall didn't reply in words but instead fingered the fabric and the base of Finn's shirt before tugging it roughly off the boy's body. His quick fingers undid the button and zipper on Finn's shorts which were flung across the room somewhere. Now the only thing keeping either of them from being completely naked was a maroon towel and a pair of yellow boxers. Marshall's smile was that of a shark's when he got eye-level with Finn's crotch and tore the boxers in half painfully slowly.

"Sit on the edge of the bed, it'll make it easier."

"Mkay," Finn mumbled. He slid out of the yellow shreds and scooted to the bed edge.

"You ready?" Marshall asked, eyeing Finn's surprisingly sizable length.

"Yeah."

Marshall's gleamed and he took in the head. Finn mewled pitifully. He swirled his tongue around it and twisted his head. Marshall took in more and more until he had all seventeen centimetres in his mouth. Finn attempted to buck his hips but couldn't escape the firm grasp that held him down. Marshall pulled off and Finn whined only to find out what he had in store. Marshall licked straight up the side and prodded Finn's slit with his tongue. He took hold of the base with his hand and pumped while his mouth entertained the head. Heat filled Finn's core and his stomach muscles clenched.

"Oh, glob. Marshall!"

"Mmh?"

"'M c-coming!"

Right on cue, Finn released into Marshall's warm mouth and he swallowed every bit of it.

"That was amazing."

"Thank you," Marshall said, standing with a flourish.

"Is that what you were talking about earlier?"

"Not even half of it."

"Oh. What's the other half?"

"This is where it gets _really_ fun, Finny. You're going to wish you had prepared for this much sexy. You have enticed me far too much to turn back now."

"Marshall?"

"Yeah?"

"Why am I letting you do these things to me? It's not like is not awesome or anything."

"So it's still awesome?"

"Yeah."

"It's because I'm a vampire."

"That's it?"

"Basically. Or else you just have a huge crush on me."

"Okay," Finn said after a bit.

"Do you know how it works?"

"Know how what works?"

"Two guys..."

Finn looked confused.

"Two guys and sex...?" Marshall tried.

"Oh. No," Finn said sheepishly.

"Hm. I don't really want to explain it. I'm just going to say this: you cannot know true bliss without agony first."

"Not really reassuring."

"It'll be fine. Trust me."

"Okay."

Marshall stood and pulled Finn into another deep kiss.

"Prop yourself up on the pillows at the head of the bed or at least just make yourself comfortable.

Finn quietly did as he was told.

"I've never done a virgin before so I guess this'll be a learning experience for the both of us."

"Yeah."

Marshall removed his towel wondering how it even managed to stay on at all while Finn watched in slight awe.

"Sorry, Finny, you're big, but I'm bigger."

"Heh, yeah."

"The blush on your face is so delicious."

Marshall hovered above Finn for a moment before attacking him with his hands and lips. Finn squirmed and moaned under the vampire's touch while Marshall's member rubbed against Finn's creating maddening friction. The immortal took Finn into his hands and jerked him off slowly gathering spit and precome.

"Finn, this may hurt at first so I'm just going to go slow. Just say stop if you need me to."

"Okay."

Marshall moved his brought his hand to Finn's entrance and lightly pressed a finger to it. Finn inhaled deeply. Marshall pressed the finger in. Finn exhaled loudly and sharply, but did not cry out.

"Keep going?"

Finn just nodded, his eyes shut tight.

Marshall's finger went deeper and pulled out again with difficulties from lack of lubricant and Finn's utter tightness. Marshall kissed Finn's neck, jaw, and lips softly and his finger quickly reentered, eliciting a loud hiss. He pulled out and pushed back in three times without stopping and then added a second finger. Finn grunted airily.

"It will work better if you try to relax."

"Easy for you to say," Finn said behind clenched teeth.

Marshall kissed Finn deeply, distracting him enough to push in a few more times. Marshall scissored his fingers and spread them apart, his mouth keeping Finn from making any noises he would have otherwise.

"I'm going to add one more, okay?" he asked.

Finn nodded.

"Remember to relax and I'll do what I can to help."

Finn nodded again.

Marshall added a third finger and thrust deeply. Then again. And again. And again. Finn did his best to relax while Marshall kept going. Eventually the pain stopped, although it wasn't quite pleasure yet. Marshall pulled out. He positioned himself in front of Finn's entrance.

"You ready?" Marshall asked.

"I think so."

"It will hurt more than my fingers."

Finn paused for a bit to breathe. "I'm ready," he said.

Marshall pushed in all the way and Finn screamed.

"Stop!" Finn managed. "Slower... please," he said through clenched teeth.

"Right, sorry."

Marshall just stayed like that for a bit, letting Finn get used to it, before slowly pulling out a ways and then back in. Marshall was cold and big and it felt awkward and painful but after a few more thrusts even that pain stopped.

"Maybe... you could go faster?" Finn asked looking up into Marshall's eyes.

"Yeah..."

Marshall did as he was asked and Finn gasped. Combined with Finn's warmth and tightness, his panting and his sheer innocence, Marshall was starting to lose control.

"You are so beautiful," Marshall whispered, his voice husky and low.

"Not... so bad... yourself."

Marshall went faster and all Finn could feel now was bliss. The immortal sucked on Finn's neck and switched his position to thrust deeply into a bundle of nerves. Finn saw stars exploding in his vision and a wave of pleasure racked his body.

"Oh glob! Marshall! Do it again! Please!" Finn whined.

And he did. Again and again. Marshall took hold of Finn's member and stroked in time to his erratic thrusting. It was all getting to be too much for the younger boy with Marshall's teeth and tongue still ravaging his neck. Finn felt heat pool in his stomach as he grew closer to ecstasy.

"Marshall!" Finn shouted.

His walls clamped around Marshall pushing him over the edge and bringing both teens to release simultaneously. Marshall pulled out slowly and lay next to Finn.

"Oh... my... glob," was all Finn could manage.

"Yeah. That was amazing." He planted a light kiss on Finn's lips before Finn fell asleep. Marshall pulled a blanket over both of them and wrapped his arms around the blonde. "You're amazing."

* * *

**AN:** Yay! I actually finished a fic! *insert personal victory dance here* And now how many of you have been left wondering what happened to Jake? Or if or how Finn got back to Ooo? Well here's when you find out. The super compressed version.

**So... What happened next? This did: **The next day when Finn woke up Marshall said that Gumball had called saying he figure out how to get Finn back to his dimension. The day after that, the machine is ready. Gumball gives Finn an interdimensional phone and tell him to call whenever he want to come back. Finn crosses the portal after sloppy goodbye makouts with Marshall in front of everyone (Fiona, Cake, LM, and Gumball). Jake was all healed up when he got back, if not a little bit worried about Finn, and had a ton of questions as to where he had been and what had happened. Finn did say he went into the portal and managed to get back out after help from the locals, but didn't mention it was an alternate dimension and that he was no longer a virgin. He goes back to visit Marshall Lee after a while and with enough reviews I might tell about this encounter.


End file.
